Tautomerism of cyclohexenone de­ri­va­ti­­ves of (2E, 4E)-1-(2-hydoxy-5-me­tyl­phenyl)-5-phenyl-2.4-pen­­­­tadiene-1-on in solu­ti­ons using NMR has been investigated. The results confirmed the for­­­ma­­tion of  O–H···O type intramolecular hydrogen bonds, keto-enol tau­­tomeric transitions in the (E)-6-acetyl-3-(2-hydroxy-5-metylphenyl)-5-styryl cyc­lo­­­hex­­­-2-en-1-one. Pos­si­bi­lity of the pre­sen­ce of keto-enol tautomerism in the investigated compound by chemical method also has been confirmed. Interaction between the (2E, 4E)-1-(2-hydoxy-5-me­tyl­phenyl)-5-phenyl-2.4-pen­­­­tadiene-1-on and cyc­lo­pentanone also have been investigated.